1. Field of the Invention
This system relates generally to bicycle suspension controls, and more specifically, this system relates to automatically interconnecting a bicycle suspension damping setting with a bicycle shifting setting
2. Description of the Related Art
Bicycles intended for off-road use, i.e., mountain bikes, commonly include a suspension assembly operably positioned between the front and/or rear wheels of the bicycle and the frame of the bicycle. The suspension assembly typically includes a shock absorber configured to absorb forces imparted to the bicycle by bumps or other irregularities of the surface on which the bicycle is being ridden. However, an undesirable consequence of incorporating a suspension assembly in a bicycle is the tendency for the shock absorber to absorb a portion of the power output of a rider of the bicycle. In some instances, i.e. when the rider is standing, the proportion of power absorbed by the shock absorber may be substantial and may drastically reduce the efficiency of the bicycle.
Numerous attempts have been made to overcome the inefficiencies related to the use of shock absorbers in connection with mountain bikes. For example, suspension may be provided only between the front wheel and the frame of the bicycle (referred to as a “hardtail” bicycle), to take advantage of the improved handling provided by the suspension while minimizing power loss by rigidly supporting the rear wheel. However, such an arrangement reduces comfort and more importantly control for the rider.
Another proposed solution is to configure the shock absorber to differentiate forces induced by the terrain and forces induced by the rider so that terrain-induced forces may be absorbed, while the absorption of rider-induced forces is reduced or substantially eliminated. One example of this type of shock absorber utilizes an inertia valve to distinguish rider-induced forces from terrain-induced forces and is described in U.S. Pat. No. 6,267,400, which is assigned to the assignee of the present invention. In one exemplary embodiment described therein, a shock absorber includes a compression fluid chamber and a reservoir fluid chamber configured for fluid communication with the compression fluid chamber. During compression motion of the shock absorber, fluid is transferred from the compression fluid chamber to the reservoir fluid chamber, which operates as a compensation chamber for fluid displaced by a shaft of the shock absorber during compression movement, as will be readily appreciated by one of skill in the art. In an illustrated embodiment of U.S. Pat. No. 6,267,400, an inertia valve is positioned between the compression fluid chamber and the reservoir fluid chamber and regulates the flow of fluid in a direction from the compression fluid chamber to the reservoir fluid chamber.
In one exemplary embodiment of the inertia valve, an inertia mass is configured to substantially prevent fluid flow to the reservoir chamber in response to a rider-induced force. Accordingly, because fluid flow from the compression fluid chamber to the reservoir fluid chamber is substantially prevented, compression movement of the shock absorber is substantially prevented because the fluid displaced by the shaft cannot be transferred to the reservoir fluid chamber. In this mode, a bicycle incorporating the shock absorber behaves in a manner similar to a hardtail. The inertia mass is further configured to permit fluid flow to the reservoir in response to a terrain-induced force above a threshold. In this mode, compression movement of the shock absorber is permitted because the fluid displaced by the shaft may be transferred to the reservoir chamber. Thus, in this mode, the bicycle obtains the benefit of rear suspension in absorbing terrain-induced forces.
An exemplary embodiment of U.S. Pat. No. 6,267,400 described immediately above provides numerous benefits when incorporated into the front or rear suspension assembly of a bicycle. Mountain bikes equipped with such shock absorbers are especially well-suited for competitive use, where a high pedaling efficiency is particularly advantageous. In addition, the availability of suspension travel in response to terrain-induced forces allows such a mountain bike to traverse rough terrain more quickly than a “hardtail” bicycle.
Bicycle shock absorbers having rider-adjustable compression and rebound damping characteristics have been used to match a desired level of pedaling efficiency and ride comfort with a type of terrain encountered. A rider may adjust the compression damping setting of a shock absorber to trade improved pedaling efficiency for improved bump absorption. For example, an adjustable shock absorber may desirably be set to a firm setting while a rider is on a steep hill climb to increase the amount of pedaling energy reaching the driven wheel and reduce the amount of pedaling energy dissipated by the suspension. Conversely, an adjustable shock absorber may desirably be set to a relatively soft compression damping setting where a rider is traveling fast downhill.
Conventional adjustable shock absorbers used in bicycle suspensions are lever actuated to allow a rider to adjust the shock setting on the fly. Commonly shock absorbers have three compression damping firmness settings: a firm setting, a medium damping setting, and a soft setting. Often, the adjustment levers are difficult for a rider to reach while cycling. Various mechanically coupled hand controls have been proposed for overcoming this lack of access to suspension adjustments. However, an additional hand control has the unintended effect of overwhelming an already busy cyclist who typically coordinates four hand controls (two shifters controls and two brake controls) during strenuous maneuvers. This potential for overwhelming a cyclist is exacerbated by the fact that when a rider encounters a steep incline or decline, they may want to modulate the brakes, shift gears, and adjust the suspension settings almost simultaneously. Moreover, less experienced riders may want the versatility offered by an easily adjustable suspension, but not be aware of the optimal suspension settings for commonly encountered riding conditions.
Conventional transmissions for bicycles include a chain transmitting pedal power from a front gear set to a rear gear set. Commonly, the front gear set includes three chain rings. A rider can shift the chain from chain ring to chain ring by selecting a gear on the derailleur. The front derailleur is a robust, almost maintenance-free mechanism that even novice riders are familiar with operating. Moreover, the position of the front derailleur often corresponds to the terrain or topography encountered by a rider. For example a small chain ring is typically chosen for particularly steep hills where a low gear is desired to increase pedaling leverage, a middle chain ring is for more moderate hills, and a large chain ring is chosen for high speed cruising or downhill descents.